Theme Park physics

The ‘Tower of Terror’ is a 400 m track that stretches for 300 m horizontally before curving
upward for 100 m . A 6 tonne pod with 16 people aboard (total mass about
7000 kg) is accelerated from rest (point A) to 160 km/h (at point B) along the horizontal
section by electromagnets that draw 2.2 megawatts for 6 s. After this the pod goes
unassisted into a vertical curve of radius 100 m, which gradually tightens to a curve of
radius 50 m (point C) before travelling vertically for the last part of the trip.
By this stage 12 s has elapsed (point D). In another 12 s the pod will be back to the start.

At the top of the curve (point C), the centripetal acceleration is 4.5 g. Calculate
the velocity at this point.